[PyTorch Bart] Split Bart into different models (#9343)

* first try

* remove old template

* finish bart

* finish mbart

* delete unnecessary line

* init pegasus

* save intermediate

* correct pegasus

* finish pegasus

* remove cookie cutter leftover

* add marian

* finish blenderbot

* replace in file

* correctly split blenderbot

* delete "old" folder

* correct "add statement"

* adapt config for tf comp

* correct configs for tf

* remove ipdb

* fix more stuff

* fix mbart

* push pegasus fix

* fix mbart

* more fixes

* fix research projects code

* finish docs for bart, mbart, and marian

* delete unnecessary file

* correct attn typo

* correct configs

* remove pegasus for seq class

* correct peg docs

* correct peg docs

* finish configs

* further improve docs

* add copied from statements to mbart

* fix copied from in mbart

* add copy statements to marian

* add copied from to marian

* add pegasus copied from

* finish pegasus

* finish copied from

* Apply suggestions from code review

* make style

* backward comp blenderbot

* apply lysandres and sylvains suggestions

* apply suggestions

* push last fixes

* fix docs

* fix tok tests

* fix imports code style

* fix doc

tests/test_tokenization_mbart.py

@@ -31,7 +31,7 @@ if _sentencepiece_available:
 
 
 if is_torch_available():
-    from transformers.models.bart.modeling_bart import shift_tokens_right
+    from transformers.models.mbart.modeling_mbart import shift_tokens_right
 
 EN_CODE = 250004
 RO_CODE = 250020
@@ -196,6 +196,7 @@ class MBartEnroIntegrationTest(unittest.TestCase):
             self.src_text, tgt_texts=self.tgt_text, return_tensors="pt"
         )
         batch["decoder_input_ids"] = shift_tokens_right(batch.labels, self.tokenizer.pad_token_id)
+
         for k in batch:
             batch[k] = batch[k].tolist()
         # batch = {k: v.tolist() for k,v in batch.items()}